Iron deficiency anemia in IBD: an overlooked comorbidity

ABSTRACT

Introduction: Iron Deficiency Anemia (IDA) is a leading cause of anemia in Inflammatory Bowel disease (IBD). IDA affects quality of life (QoL) and lead to developmental and cognitive abnormalities. Diagnosis of IDA in IBD is complicated as biochemical tests available at present cannot help distinguish between IDA and anemia of chronic disease. Soluble transferrin receptor ferritin index has been gaining popularity as it can diagnose IDA in presence of chronic inflammation. ECCO guidelines recommend a Hb increase of >2 g/dL and a TfS of >30% within 4 weeks as adequate therapeutic response. IV iron is preferred over oral iron as it bypasses gastrointestinal tract, rapidly increases haemoglobin, and is not associated with intestinal inflammation. Our aim in this review is to provide apathway for physicians to help them diagnose and appropriately treat IDA in IBD.

Areas covered: In this review article, we have discussed current diagnosis and treatment in detail and have proposed new directions on how future research can help manage IDA in IBD effectively.

Expert opinion: Understanding the pathogenesis of IDA in IBD will further lead to exploring new potential diagnostic tests and treatment regimens for effective management of IDA in IBD

KEYWORDS:

• Iron deficiency anemia
• Inflammatory Bowel Disease
• intravenous iron therapy
• ulcerative colitis
• Crohn’s Disease

Article highlights

• IDA is a common and often overlooked extraintestinal manifestation of IBD

• IDA has been shown to negatively impact patient’s QoL, physical performance levels, cognitive functioning and concentration levels. If left untreated, it may lead to high output heart failure, extreme fatigue, and depression.

• Diagnosis of IDA is challenging as laboratory findings often overlap with ACD. Cutoff values for diagnostic tests are different to diagnose IDA in IBD patients. Currently, transferrin saturation is helpful to differentiate IDA from ACD. Ferritin of <100 μg/L can also help differentiate ACD and IDA if CRP is elevated.

• sTfR-F index has shown promising results as it can help differentiate IDA from ACD in IBD patients because of its high sensitivity and specificity. Although, further studies are required to validate this test for further use in the future.

• Hepcidin levels can also be useful in the future but at present there is no cut-off value established to help differentiate between IDA and ACD.

• Oral iron therapy should be reserved to mild asymptomatic cases of IDA in IBD. IV iron therapy especially ferric carboxymaltose, is the mainstay treatment of IDA given its high tolerability, absorption and effectiveness in rapid repletion of iron stores in IBD population.

• Patients should be monitored for IDA recurrence every 3 months for 1 year and then 6–12 months. As per ECCO guidelines, patients should be immediately started on oral or IV iron therapy as soon as ferritin levels are below 100.

Specific author contributions

Yash Shah has substantially contributed to the design of the article, interpreting the relevant literature. Yash Shah and Dhruvan Patel have contributed to drafting of the manuscript. Nabeel Khan has contributed to the conception and critical revision of the review article for important intellectual content.

Declaration of interest

Nabeel Khan has received research funding from Pfizer, Luitpold, Takeda Pharmaceuticals, and Samsung. Dhruvan Patel has nothing to disclose regarding conflicts of interest. Yash Shah has nothing to disclose regarding conflicts of interest.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose